Mathias Dezetter

Thermal and hydric biology of the European adder Viperas berus

Thesis topic: Conflicts between water and thermal balance during reproduction: a basis for climate vulnerability in a viviparous reptile

The study of the combined effects of global warming and changes in water availability is necessary to better understand and mitigate the impacts of climate change on biodiversity. Much work has examined the impact of thermal conditions on terrestrial ectotherms, but water-related stresses remain under-recognized. Yet, global warming implies joint changes in thermal and water conditions that are difficult to predict from single-factor studies. My thesis project aims to develop a thorough understanding of the interactions between hydroregulation and thermoregulation at the time of gestation in terrestrial ectotherms. I focus on the thermal and hydric biology of the European adder Vipera berus, an Euro-Siberian species that exploits cold and humid environments and has a long gestation period. My PhD project is based on experimental work carried out at the CEBC which includes measurements of individual thermoregulatory and hydroregulatory capacity and experiments on chronic manipulation of thermal conditions and water access, especially during gestation. These approaches provide an understanding of the physiological niche of this species and the response to different climate change scenarios.

The fundamental questions of my doctoral project are:
– What are the physiological conflicts between water and heat requirements at the individual level?
– What is the window of sensitivity to water restriction during gestation and how do thermal and water conditions interact?
– What are the mechanisms of acclimatization and adaptation to joint thermal and water stress?

PhD student in the ECOPHY team under the supervision of Olivier Lourdais (CEBC) and Jean-François Le Galliard (iEES Paris)
Doctoral School 227 MNHN – Sorbonne University